Darwin Runtime Engineer, Core OS

Apple • Cupertino, CA

2d

About The Position

The Darwin Runtime Engineer will develop and evolve low-level user-space libraries and runtime technologies that underpin Apple operating systems, including Grand Central Dispatch (GCD), XPC, pthread, and malloc. The role involves building foundational software used across Apple devices and operating systems, with a focus on performance, security, and the interaction between operating systems and hardware.

The engineer will work autonomously, develop expertise across new technical domains, contribute to technical leadership, drive design discussions, and support peers through code reviews. The position offers substantial technical ownership and collaboration across a range of technologies.

Requirements

• Fluency in the C programming language.
• At least 6 years of experience with UNIX-like systems.
• System design and architecture skills.
• Strong understanding of operating system fundamentals, including threading, synchronization primitives, inter-process communication, scheduling, and virtual memory.
• Excellent collaborative skills and ability to work with a team to design system architecture.
• Bachelor’s or master’s degree in Computer Science, or an equivalent degree.

Nice To Haves

• Knowledge of operating system implementation, hardware architecture, and assembly programming.
• Knowledge of Swift or Objective-C.
• Experience with interface and/or API design.
• Experience with lldb or gdb.
• Experience using generative AI tools for software development.

Responsibilities

• Design and implement new features and APIs for Darwin Runtime technologies such as GCD, XPC, pthread, and malloc.
• Develop and maintain high-performance runtime libraries that handle memory management and component lifecycle across different execution environments.
• Optimize code generation, runtime performance, and memory usage to meet strict low-level system performance requirements.
• Participate in all phases of the software development cycle, from problem definition and design through implementation, testing, and debugging.
• Diagnose and resolve issues across different layers of the stack.
• Write unit and integration tests for new and existing code.
• Work with cross-functional teams to enable developer and product requirements.
• Drive technical design discussions and elevate peers through code reviews.

What This Job Offers

• Job Type: Full-time
• Career Level: Senior